Abstract
Often the scan gives all the information required for the further management of the patient. Because the tests are so "innocuous" they are ideal as screening tests, particularly for brain tumors, thyroid tumors, liver metastases, liver or spleen enlargement and early involvement of bone by tumor. The main disadvantages of scanning are the time involved and the cost of the apparatus and radiopharmaceuticals. The time required for scans is decreasing with the introduction of the use of high activities of shortlived isotopes. Newer scanners use a multi-crystal array which permit complete examinations in a few min. while the [gamma]-camera produces an image in sec.